Treatment regimens, protocols, dosage, and indications for UVA1 phototherapy: facts and controversies.

During the last three decades, ultraviolet A1 (UVA1) phototherapy has emerged as a specific phototherapeutic modality with distinct modes of action and some well established indications. Atopic dermatitis, localized scleroderma, and systemic lupus erythematosus seem to be the conditions with the best evidence regarding efficacy and safety of UVA1 phototherapy. Further indications for UVA1 include subacute prurigo, lichen sclerosus, dyshidrotic dermatitis, cutaneous T cell lymphoma, urticaria pigmentosa, and pityriasis rosea; nevertheless, there are some unknowns, uncertainties, and controversies concerning short- and long-term side effects, efficacy and dosage regimens of UVA1 phototherapy in some conditions. We describe and discuss treatment regimens, protocols, dosage, and indications for UVA1 phototherapy.